The invention relates to the design and structure of attachments and their mounting system for firearms. More specifically, the invention relates to tactical attachments mounted to a wide variety of firearms such as handguns, shotguns, and long guns.
Users of firearms often attach removable devices such as laser sights, flashlights, and other accessories to their weapon. Typically, these attachments require special brackets and mounting systems which are expensive and custom built, each “tactical” device or attachment having its own bracketing or mount. These custom mounts further require alignment with the firearm's point of aim, which can be time consuming to set up and are subject to misalignment if physically bumped during use. Some bracketing interferes with the use of the aiming sights on the weapon which can further hinder use.
If the weapon stores ammunition in a tubular style magazine, tactical attachments may be mounted to the end of the ammunition tube, replacing the stock cap employed by the manufacturer. This mounting method has the advantage of automatic alignment with the weapon's point of aim. Typically, this method has been utilized with pump style shotguns, although it may also be employed with other longs guns having tube magazines such as lever action rifles, for example.
FIG. 1 (Prior Art) is a side view 100 of a shotgun having an ammunition tube 106. Ammunition tube 106 and pump slide 104 are situated below the barrel 102. Ammunition spring 110 provides the force to feed ammunition (not shown) in the action of the weapon (not shown) for firing. Spring 110 is held within the ammunition tube 106 via cap 112 which is threaded onto ammunition tube 106 via threads 108. One example manufacturer making firearms as shown in FIG. 1 is Remington Arms Company LLC, of Madison N.C.
FIG. 17a (Prior Art) is a side view 1700 of a shotgun having an ammunition tube 1706 containing an integral ammunition spring. Retaining screw 1702 threads into ammunition tube 1706 and serves to help retain barrel 102 via lug 1704. FIG. 17b is an end view 1701 of the shotgun and barrel retaining lug 1704, showing 20 machined cavities 1708, which engage a ball detent fabricated within retaining screw 1702. FIG. 17c is a side view of retaining screw 1702 having a spring loaded ball detent device 1710. Firearms having this type of barrel retention system are distinguished from those illustrated in FIG. 1 (Prior Art), as prior art attachments designed for the firearms of FIG. 1 will not fit firearms as shown in FIGS. 17a,b,c (Prior Art). As an example, one manufacturer building shotguns shown in FIG. 17 is O.F. Mossberg and Sons, Inc., of North Haven Conn. The differences in construction between these two types of firearms often forces firearm owners to purchase redundant tactical attachments, which can be expensive, particularly for military or police organizations which may have both types of firearms in inventory for their personnel.
Patent Application Publication US 2010/0277896 A1 by Oehlkers discloses an example of a flashlight threaded on to the ammunition tube of a shotgun. The device combines a flashlight with extended ammunition capacity. One weakness of this approach is that a special flashlight device must be manufactured for every make and model of shotgun or long gun, which can be expensive for owners of multiple weapons. Another weakness is that the ammunition spring 110 is exposed every time the flashlight is removed or replaced with another device, which can lead to the spring launching from the ammunition tube 106 as the attachment is removed. It may also be difficult to re-install the spring if the magazine tube is full of ammunition. This can prove to be disruptive, particularly for peace officers or military personnel who rely on rapid exchange of tactical attachments during moments of high duress. Further, a thread on device 202, such as that shown in FIG. 2, may have the activation switch 204 end up in different locations, depending on the starting position prior to threading the unit 202 on. This can be troubling for military and peace officers who require “hands off” familiarity of their weapon, and can ill afford taking their eyes from the sight picture ahead to find the flashlight on/off switch.
U.S. Pat. No. 5,727,346 to Lazzarini et. al. discloses a device for mounting a flashlight or similar device into a holder attached to (below) slide 104. This system has the disadvantage that the device is mounted to a movable part, and therefore the accuracy (particularly of a laser illumination sight) is questionable. Furthermore, tactical attachments such as door breaching tools or ammunition extension tubes are not compatible with this mounting system.
U.S. Pat. No. 6,565,226 to Cummings discloses flashlight mounting system wherein the flashlight is mounted with a portion of the ammunition tube 106. This system has the disadvantage of consuming ammunition capacity, as a significant portion of the flashlight is mounted within the ammunition tube. It also requires the use of tools for the removal of the flashlight and adapters which would not be suitable for military or police field use. It is also suitable only for the larger gauge shotgun calibers, due the outside diameter requirements of the flashlight.
One method employed in the prior art for mounting gun sights, flashlights, laser sights, and other accessories to a firearm utilizes the Weaver or Picatinny Rail system. These are machined rails that can be attached to a firearm (or are built in to a component like a barrel or receiver) in a variety locations and via a wide variety of methods. Early versions of this system were known as Weaver rails, developed primarily for mounting telescopic type gun sights. These systems were not standardized, since the configurations were developed for a particular scope or application. Later, a standardized system called the Picatinny rail was provided for the US Military, which conformed to Mil-STD 1913. FIGS. 23a-e, 24a,b (Prior Art) illustrate examples of these auxiliary accessory rail mount systems. Both the Weaver and Picatinny rail systems have similar cross section profiles (FIGS. 23a,c Prior Art). The differences lie in the width of the grooves and lands cut in the upper surface of the rail. The grooves cross cut in the upper surface of the rail are known as “recoil grooves”, and are designed as a “stop” to reduce the impact of firearm recoil on the positioning of the device mounted on the upper surface of the rail. This can be critical for gun sights which cannot move during and after the discharge of the weapon.
Turning to the figures, FIG. 23a (Prior Art) is a front view 2300 of a Picatinny (or Weaver) auxiliary rail mount 2302. As shown, the upper portion has a dovetail which is used to mount devices via a clamp system. FIG. 23b (Prior Art) is a side view 2301 of rail mount 2302. This view shows the grooves and lands 2308. The width 2306 of a groove and the width 2304 of a land are specified and standardized in the Picatinny rail system by Mil-Std 1913, but are unspecified in a Weaver rail. The grooves between land 2308 are used to facilitate hardware (rods and bolts) which bear on the lands on either side of the groove, providing a hard stop which prevents motion during recoil. FIG. 23c (Prior Art) is a cross section view 2303 through section A-A of FIG. 23b. FIG. 23d (Prior Art) is a top view 2305 of auxiliary rail mount 2302. FIG. 23e (Prior Art) is a cross section view 2307 of a auxiliary rail mount 2302 with an example accessory clamp mount 2312 attached to the rail 2302. A typical clamp mount 2312 will be machined to engage the dovetails on the rail, and utilize a bolt 2314 and a floating portion 2310 to lock position on rail 2302 when the bolt 2314 is tightened. FIG. 24a (Prior Art) is a side view 2401 of a Picatinny auxiliary rail mounted to the cooling rib on the barrel of a shotgun. FIG. 24b (Prior Art) is an end view 2400 via section B-B of FIG. 24a. The advantage of the Picatinny/Weaver auxiliary rail mount system for attaching accessories such as scopes, sights, and lights is that the system is standardized. This means there is a wide variety of components available that fit this rail system. The downside is that most of these accessories are mounted with hardware that is bolted to the rail, requiring tools for the removal. Further, many precision devices like sights or scopes cannot be removed and remounted without re-calibration, which is time consuming and not practical in the field.
These and other limitations of the prior art will become apparent to those of skill in the art upon a reading of the following descriptions and a study of the several figures of the drawing.